U.S. patent number 11,452,145 [Application Number 16/875,462] was granted by the patent office on 2022-09-20 for sequence-based random access channel (rach) occasion.
This patent grant is currently assigned to QUALCOMM Incorporated. The grantee listed for this patent is QUALCOMM Incorporated. Invention is credited to Kapil Bhattad, Tanumay Datta, Jing Sun, Ananta Narayanan Thyagarajan, Xiaoxia Zhang.
United States Patent |
11,452,145 |
Sun , et al. |
September 20, 2022 |
Sequence-based random access channel (RACH) occasion
Abstract
This disclosure provides systems, methods, and apparatuses for
random access channel (RACH) occasions that overlap each other in
time and frequency. In one aspect, the RACH occasions may use
different preamble sequence sets. A base station may signal
configuration information indicating the preamble sequence sets for
the RACH occasions and information indicating a time-frequency
resource allocation of the RACH occasions. A UE may perform a
random access procedure in accordance with the configuration
information.
Inventors: |
Sun; Jing (San Diego, CA),
Datta; Tanumay (Bangalore, IN), Bhattad; Kapil
(Bangalore, IN), Thyagarajan; Ananta Narayanan
(Bangalore, IN), Zhang; Xiaoxia (San Diego, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Assignee: |
QUALCOMM Incorporated (San
Diego, CA)
|
Family
ID: |
1000006571523 |
Appl.
No.: |
16/875,462 |
Filed: |
May 15, 2020 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200374943 A1 |
Nov 26, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
May 22, 2019 [IN] |
|
|
201941020287 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
72/0446 (20130101); H04W 56/001 (20130101); H04W
72/0453 (20130101); H04W 74/0841 (20130101) |
Current International
Class: |
H04W
74/08 (20090101); H04W 72/04 (20090101); H04W
56/00 (20090101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Ad-Hoc Chair (Ericsson): "Chairman's notes of AI 7.2.2 Study on
NR-based Access to Unlicensed Spectrum," 3GPP Draft, 3GPP TSG-RAN
WG1 Meeting #97, R1-1907846, 3rd Generation Partnership Project
(3GPP), Mobile Competence Centre, 650, Route Des Lucioles, F-06921,
Sophia-Antipolis Cedex, France, vol. RAN WG1. No. Reno. USA, May
13, 2019-May 17, 2019, May 20, 2019 (May 20, 2019), XP051740119, 8
pages, Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/tsg%5Fran/WG1%5FRL1/TSGR1%5F97/Docs/R1%2D1907846%-
2Ezip [retrieved on May 20, 2019] section 7.2.2.1.1 "Initial access
signals/channels". cited by applicant .
Fujitsu: "Consideration on PRACH in NR-U," 3GPP Draft, 3GPP TSG RAN
WG1 #97, R1-1906430, Consideration on PRACH in NR-U, 3rd Generation
Partnership Project (3GPP), Mobile Competence Centre, 650, Route
Des Lucioles, F-06921, Sophia-Antipolis Cedex, France, vol. RAN
WG1. No. Reno. USA, May 13, 2019-May 17, 2019, May 13, 2019 (May
13, 2019), XP051727880, 4 pages, Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/Meetings%5F3GPP%5FSYNC/RAN1/Docs/R1%2D1906430%2Ez-
ip [retrieved on May 13, 2019] the whole document. cited by
applicant .
International Search Report and Written
Opinion--PCT/US2020/033417--ISA/EPO--dated Aug. 26, 2020. cited by
applicant .
Qualcomm Incorporated: "Feature Lead Summary on Initial Access
Signals and Channels for NR-U," 3GPP Draft, 3GPP TSG RAN WG1
Meeting #97, R1-1907883, FL Summary 7.2.2.1.1 V2, 3rd Generation
Partnership Project (3GPP), Mobile Competence Centre, 650, Route
Des Lucioles, F-06921, Sophia-Antipolis Cedex, France, vol. RAN
WG1. No. Reno, USA, May 13, 2019-May 17, 2019, May 17, 2019 (May
17, 2019). XP051740144, 44 pages, Retrieved from the Internet: URL:
http://www.3gpp.org/ftp/tsg%5Fran/WG1%5FRL1/TSGR1%5F97/Docs/R1%2D1907883%-
2Ezip [retrieved on May 17, 2019] section 1 "Introduction" section
2.2 "PRACH". cited by applicant.
|
Primary Examiner: Nguyen; Brian D
Attorney, Agent or Firm: Harrity & Harrity, LLP \
Qualcomm
Claims
What is claimed is:
1. A method of wireless communication performed by an apparatus of
a user equipment (UE), comprising: receiving configuration
information associated with two or more overlapping random access
channel (RACH) occasions, wherein the configuration information
indicates preamble sequence sets for the two or more overlapping
RACH occasions, wherein each of the two or more overlapping RACH
occasions is associated with a respective preamble sequence set,
and wherein the two or more overlapping RACH occasions overlap in
time and frequency; selecting a RACH occasion, of the two or more
overlapping RACH occasions; and transmitting a RACH preamble on the
selected RACH occasion in accordance with the respective preamble
sequence set associated with the selected RACH occasion.
2. The method of claim 1, wherein the RACH preamble occupies a
threshold channel bandwidth of a channel in accordance with an
occupied channel bandwidth requirement of the UE.
3. The method of claim 1, further comprising: receiving a
synchronization signal block (SSB) that identifies a particular
time-frequency resource allocation, wherein transmitting the RACH
preamble on the selected RACH occasion is based at least in part on
the selected RACH occasion being associated with the particular
time-frequency resource allocation.
4. The method of claim 1, wherein the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more overlapping RACH occasions, and wherein preamble
sequence sets for one or more other RACH occasions, of the two or
more overlapping RACH occasions, are derived based at least in part
on the first preamble sequence set.
5. The method of claim 1, wherein the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more overlapping RACH occasions, and wherein a second
preamble sequence set for a second RACH occasion of the two or more
overlapping RACH occasions starts at a last-used root and a next
sequence after a last-used sequence of the first preamble sequence
set.
6. The method of claim 1, wherein the configuration information
identifies a first preamble sequence set for a first RACH occasion,
of the two or more overlapping RACH occasions, and wherein a second
preamble sequence set for a second RACH occasion of the two or more
overlapping RACH occasions starts at a next root after a last-used
root of the first preamble sequence set.
7. The method of claim 1, wherein the configuration information
identifies respective root sequences for the preamble sequence
sets.
8. The method of claim 1, wherein the configuration information
indicates a number of RACH occasions associated with a particular
time-frequency resource allocation.
9. A method of wireless communication performed by an apparatus of
a network entity, comprising: transmitting configuration
information associated with two or more overlapping random access
channel (RACH) occasions, wherein the configuration information
indicates preamble sequence sets for the two or more overlapping
RACH occasions, wherein each of the two or more overlapping RACH
occasions is associated with a respective preamble sequence set,
and wherein the two or more overlapping RACH occasions overlap in
time and frequency; and receiving a RACH preamble on a selected
RACH occasion, of the two or more overlapping RACH occasions, in
accordance with the respective preamble sequence set associated
with the selected RACH occasion.
10. The method of claim 9, wherein the RACH preamble occupies a
threshold channel bandwidth of a channel in accordance with an
occupied channel bandwidth requirement.
11. The method of claim 9, further comprising: transmitting a
synchronization signal block (SSB) that identifies a particular
time-frequency resource allocation, wherein receiving the RACH
preamble on the selected RACH occasion is based at least in part on
the selected RACH occasion being associated with the particular
time-frequency resource allocation.
12. The method of claim 9, wherein the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more overlapping RACH occasions, and wherein preamble
sequence sets for one or more other RACH occasions, of the two or
more overlapping RACH occasions, are derived based at least in part
on the first preamble sequence set.
13. The method of claim 9, wherein the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more overlapping RACH occasions, and wherein a second
preamble sequence set for a second RACH occasion of the two or more
overlapping RACH occasions starts at a last-used root and a next
sequence after a last-used sequence of the first preamble sequence
set.
14. The method of claim 9, wherein the configuration information
identifies a first preamble sequence set for a first RACH occasion,
of the two or more overlapping RACH occasions, and wherein a second
preamble sequence set for a second RACH occasion of the two or more
overlapping RACH occasions starts at a next root after a last-used
root of the first preamble sequence set.
15. The method of claim 9, wherein the configuration information
identifies respective root sequences for the preamble sequence
sets.
16. The method of claim 9, wherein the configuration information
indicates a number of RACH occasions associated with a particular
time-frequency resource allocation.
17. An apparatus of a user equipment (UE) for wireless
communication, comprising: a first interface configured to obtain
configuration information associated with two or more overlapping
random access channel (RACH) occasions, wherein the configuration
information indicates preamble sequence sets for the two or more
overlapping RACH occasions, wherein each of the two or more
overlapping RACH occasions is associated with a respective preamble
sequence set, and wherein the two or more overlapping RACH
occasions overlap in time and frequency; a processing system
configured to select a RACH occasion, of the two or more
overlapping RACH occasions; and a second interface configured to
output a RACH preamble for transmission on the selected RACH
occasion in accordance with the respective preamble sequence set
associated with the selected RACH occasion.
18. The apparatus of claim 17, wherein the RACH preamble occupies a
threshold channel bandwidth of a channel in accordance with an
occupied channel bandwidth requirement of the UE.
19. The apparatus of claim 17, wherein the configuration
information identifies a first preamble sequence set for a first
RACH occasion of the two or more overlapping RACH occasions, and
wherein preamble sequence sets for one or more other RACH
occasions, of the two or more overlapping RACH occasions, are
derived based at least in part on the first preamble sequence
set.
20. The apparatus of claim 17, wherein the configuration
information identifies a first preamble sequence set for a first
RACH occasion of the two or more overlapping RACH occasions, and
wherein a second preamble sequence set for a second RACH occasion
of the two or more overlapping RACH occasions starts at a last-used
root and a next sequence after a last-used sequence of the first
preamble sequence set.
21. The apparatus of claim 17, wherein the configuration
information identifies a first preamble sequence set for a first
RACH occasion, of the two or more overlapping RACH occasions, and
wherein a second preamble sequence set for a second RACH occasion
of the two or more overlapping RACH occasions starts at a next root
after a last-used root of the first preamble sequence set.
22. The apparatus of claim 17, wherein the configuration
information identifies respective root sequences for the preamble
sequence sets.
23. The apparatus of claim 17, wherein the configuration
information indicates a number of RACH occasions associated with a
particular time-frequency resource allocation.
24. The apparatus of claim 17, wherein the first interface is
further configured to: receive a synchronization signal block (SSB)
that identifies a particular time-frequency resource allocation,
wherein outputting the RACH preamble on the selected RACH occasion
is based at least in part on the selected RACH occasion being
associated with the particular time-frequency resource
allocation.
25. An apparatus of a network entity for wireless communication,
comprising: a first interface configured to output configuration
information associated with two or more overlapping random access
channel (RACH) occasions, wherein the configuration information
indicates preamble sequence sets for the two or more overlapping
RACH occasions, wherein each of the two or more overlapping RACH
occasions is associated with a respective preamble sequence set,
and wherein the two or more overlapping RACH occasions overlap in
time and frequency; and a second interface configured to obtain a
RACH preamble on a selected RACH occasion, of the two or more
overlapping RACH occasions, in accordance with the respective
preamble sequence set associated with the selected RACH
occasion.
26. The apparatus of claim 25, wherein the RACH preamble occupies a
threshold channel bandwidth of a channel in accordance with an
occupied channel bandwidth requirement.
27. The apparatus of claim 25, wherein the first interface is
further configured to: transmit a synchronization signal block
(SSB) that identifies a particular time-frequency resource
allocation, wherein obtaining the RACH preamble on the selected
RACH occasion is based at least in part on the selected RACH
occasion being associated with the particular time-frequency
resource allocation.
28. The apparatus of claim 25, wherein the configuration
information identifies a first preamble sequence set for a first
RACH occasion of the two or more overlapping RACH occasions, and
wherein preamble sequence sets for one or more other RACH
occasions, of the two or more overlapping RACH occasions, are
derived based at least in part on the first preamble sequence
set.
29. The apparatus of claim 25, wherein the configuration
information identifies a first preamble sequence set for a first
RACH occasion of the two or more overlapping RACH occasions, and
wherein a second preamble sequence set for a second RACH occasion
of the two or more overlapping RACH occasions starts at a last-used
root and a next sequence after a last-used sequence of the first
preamble sequence set.
30. The apparatus of claim 25, wherein the configuration
information identifies a first preamble sequence set for a first
RACH occasion, of the two or more overlapping RACH occasions, and
wherein a second preamble sequence set for a second RACH occasion
of the two or more overlapping RACH occasions starts at a next root
after a last-used root of the first preamble sequence set.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This Patent application claims priority to Indian Patent
Application No. 201941020287, filed on May 22, 2019, entitled
"SEQUENCE-BASED RANDOM ACCESS CHANNEL (RACH) OCCASION," and
assigned to the assignee hereof. The disclosure of the prior
application is considered part of and is incorporated by reference
in this Patent application.
TECHNICAL FIELD
Aspects of the present disclosure relate generally to wireless
communication, and more particularly, to techniques for a
sequence-based random access channel (RACH) occasion.
DESCRIPTION OF THE RELATED TECHNOLOGY
Wireless communication systems are widely deployed to provide
various telecommunication services such as telephony, video, data,
messaging, and broadcasts. Typical wireless communication systems
may employ multiple-access technologies capable of supporting
communication with multiple users by sharing available system
resources (for example, bandwidth, transmit power, etc.). Examples
of such multiple-access technologies include code division multiple
access (CDMA) systems, time division multiple access (TDMA)
systems, frequency-division multiple access (FDMA) systems,
orthogonal frequency-division multiple access (OFDMA) systems,
single-carrier frequency-division multiple access (SC-FDMA)
systems, time division synchronous code division multiple access
(TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced
is a set of enhancements to the Universal Mobile Telecommunications
System (UMTS) mobile standard promulgated by the Third Generation
Partnership Project (3GPP).
A wireless communication network may include a number of base
stations (BSs) that can support communication for a number of user
equipment (UEs). A user equipment (UE) may communicate with a base
station (BS) via the downlink (DL) and uplink (UL). The DL (or
forward link) refers to the communication link from the BS to the
UE, and the UL (or reverse link) refers to the communication link
from the UE to the BS. As will be described in more detail herein,
a BS may be referred to as a NodeB, an LTE evolved nodeB (eNB), a
gNB, an access point (AP), a radio head, a transmit receive point
(TRP), a New Radio (NR) BS, a 5G NodeB, or the like.
The above multiple access technologies have been adopted in various
telecommunication standards to provide a common protocol that
enables different UEs to communicate on a municipal, national,
regional, and even global level. NR, which also may be referred to
as 5G, is a set of enhancements to the LTE mobile standard
promulgated by the Third Generation Partnership Project (3GPP). NR
is designed to better support mobile broadband Internet access by
improving spectral efficiency, lowering costs, improving services,
making use of new spectrum, and better integrating with other open
standards using orthogonal frequency division multiplexing (OFDM)
with a cyclic prefix (CP) (CP-OFDM) on the DL, using CP-OFDM or
SC-FDM (for example, also known as discrete Fourier transform
spread OFDM (DFT-s-OFDM)) on the UL (or a combination thereof), as
well as supporting beamforming, multiple-input multiple-output
(MIMO) antenna technology, and carrier aggregation.
SUMMARY
The systems, methods and devices of this disclosure each have
several innovative aspects, no single one of which is solely
responsible for the desirable attributes disclosed herein.
One innovative aspect of the subject matter described in this
disclosure can be implemented in a method of wireless communication
performed by an apparatus of a user equipment (UE). The method may
include receiving configuration information associated with two or
more random access channel (RACH) occasions, where the
configuration information indicates preamble sequence sets for the
two or more RACH occasions, where each of the two or more RACH
occasions is associated with a respective preamble sequence set;
selecting a RACH occasion, of the two or more RACH occasions; and
transmitting a RACH preamble on the selected RACH occasion in
accordance with the preamble sequence set associated with the RACH
occasion.
In some implementations, the RACH preamble occupies a threshold
channel bandwidth of a channel in accordance with an occupied
channel bandwidth requirement of the UE.
In some implementations, each RACH occasion of the two or more RACH
occasions is associated with a same time-frequency resource
allocation.
In some implementations, the two or more RACH occasions are
associated with respective time-frequency resource allocations.
In some implementations, the method may include receiving a
synchronization signal block (SSB) that identifies a particular
time-frequency resource allocation of the respective time-frequency
resource allocations, where transmitting the RACH preamble on the
selected RACH occasion is based on the selected RACH occasion being
associated with the particular time-frequency resource
allocation.
In some implementations, the configuration information identifies a
first preamble sequence set for a first RACH occasion of the two or
more RACH occasions, where preamble sequence sets for one or more
other RACH occasions, of the two or more RACH occasions, are
derived based on the first preamble sequence set.
In some implementations, the configuration information identifies a
first preamble sequence set for a first RACH occasion of the two or
more RACH occasions, where a second preamble sequence set for a
second RACH occasion of the two or more RACH occasions starts at a
last-used root and a next sequence after a last-used sequence of
the first preamble sequence set.
In some implementations, the configuration information identifies a
first preamble sequence set for a first RACH occasion, of the two
or more RACH occasions, where a second preamble sequence set for a
second RACH occasion of the two or more RACH occasions starts at a
next root after a last-used root of the first preamble sequence
set.
In some implementations, the configuration information identifies
respective root sequences for the respective preamble sequence
sets.
In some implementations, the configuration information indicates a
number of RACH occasions associated with a particular
time-frequency resource allocation.
Another innovative aspect of the subject matter described in this
disclosure can be implemented in an apparatus of a UE for wireless
communication. The apparatus may include a first interface
configured to obtain configuration information associated with two
or more RACH occasions, where the configuration information
indicates preamble sequence sets for the two or more RACH
occasions, where each of the two or more RACH occasions is
associated with a respective preamble sequence set; a processing
system configured to select a RACH occasion, of the two or more
RACH occasions; and a second interface configured to output a RACH
preamble for transmission on the selected RACH occasion in
accordance with the preamble sequence set associated with the RACH
occasion.
Another innovative aspect of the subject matter described in this
disclosure can be implemented in a non-transitory computer-readable
medium. The non-transitory computer-readable medium may store one
or more instructions for wireless communication. The one or more
instructions, when executed by one or more processors of a UE, may
cause the one or more processors to receive configuration
information associated with two or more RACH occasions, where the
configuration information indicates preamble sequence sets for the
two or more RACH occasions, where each of the two or more RACH
occasions is associated with a respective preamble sequence set;
select a RACH occasion, of the two or more RACH occasions; and
transmit a RACH preamble on the selected RACH occasion in
accordance with the preamble sequence set associated with the RACH
occasion.
Another innovative aspect of the subject matter described in this
disclosure can be implemented in an apparatus for wireless
communication. The apparatus may include means for receiving
configuration information associated with two or more RACH
occasions, where the configuration information indicates preamble
sequence sets for the two or more RACH occasions, where each of the
two or more RACH occasions is associated with a respective preamble
sequence set; means for selecting a RACH occasion, of the two or
more RACH occasions; and means for transmitting a RACH preamble on
the selected RACH occasion in accordance with the preamble sequence
set associated with the RACH occasion. In some implementations, the
apparatus may include means for receiving a synchronization signal
block that identifies a particular time-frequency resource
allocation of the respective time-frequency resource
allocations.
Another innovative aspect of the subject matter described in this
disclosure can be implemented in a method of wireless communication
performed by an apparatus of a base station (BS). The method may
include transmitting configuration information associated with two
or more RACH occasions, where the configuration information
indicates preamble sequence sets for the two or more RACH
occasions, where each of the two or more RACH occasions is
associated with a respective preamble sequence set; and receiving a
RACH preamble on a selected RACH occasion, of the two or more RACH
occasions, in accordance with the preamble sequence set associated
with the RACH occasion.
In some implementations, the RACH preamble occupies a threshold
channel bandwidth of a channel in accordance with an occupied
channel bandwidth requirement of the UE.
In some implementations, the two or more RACH occasions are
associated with respective time-frequency resource allocations.
In some implementations, the method may include transmitting an SSB
that identifies a particular time-frequency resource allocation of
the respective time-frequency resource allocations, where receiving
the RACH preamble on the selected RACH occasion is based on the
selected RACH occasion being associated with the particular
time-frequency resource allocation.
In some implementations, the configuration information identifies a
first preamble sequence set for a first RACH occasion of the two or
more RACH occasions, where preamble sequence sets for one or more
other RACH occasions, of the two or more RACH occasions, are
derived based on the first preamble sequence set.
In some implementations, the configuration information identifies a
first preamble sequence set for a first RACH occasion of the two or
more RACH occasions, where a second preamble sequence set for a
second RACH occasion of the two or more RACH occasions starts at a
last-used root and a next sequence after a last-used sequence of
the first preamble sequence set.
In some implementations, the configuration information identifies a
first preamble sequence set for a first RACH occasion, of the two
or more RACH occasions, where a second preamble sequence set for a
second RACH occasion of the two or more RACH occasions starts at a
next root after a last-used root of the first preamble sequence
set.
In some implementations, the configuration information identifies
respective root sequences for the respective preamble sequence
sets.
In some implementations, the configuration information indicates a
number of RACH occasions associated with a particular
time-frequency resource allocation.
Another innovative aspect of the subject matter described in this
disclosure can be implemented in an apparatus of a BS for wireless
communication. The apparatus may include memory and one or more
processors operatively coupled to the memory. The memory and the
one or more processors may be configured to transmit configuration
information associated with two or more RACH occasions, where the
configuration information indicates preamble sequence sets for the
two or more RACH occasions, where each of the two or more RACH
occasions is associated with a respective preamble sequence set;
and receive a RACH preamble on a selected RACH occasion, of the two
or more RACH occasions, in accordance with the preamble sequence
set associated with the RACH occasion.
Another innovative aspect of the subject matter described in this
disclosure can be implemented in a non-transitory computer-readable
medium. The non-transitory computer-readable medium may store one
or more instructions for wireless communication. The one or more
instructions, when executed by one or more processors of a BS, may
cause the one or more processors to transmit configuration
information associated with two or more RACH occasions, where the
configuration information indicates preamble sequence sets for the
two or more RACH occasions, where each of the two or more RACH
occasions is associated with a respective preamble sequence set;
and receive a RACH preamble on a selected RACH occasion, of the two
or more RACH occasions, in accordance with the preamble sequence
set associated with the RACH occasion.
Another innovative aspect of the subject matter described in this
disclosure can be implemented in an apparatus for wireless
communication. The apparatus may include means for transmitting
configuration information associated with two or more RACH
occasions, where the configuration information indicates preamble
sequence sets for the two or more respective occasions, where each
of the two or more RACH occasions is associated with a respective
preamble sequence set; and means for receiving a RACH preamble on a
selected RACH occasion, of the two or more RACH occasions, in
accordance with the preamble sequence set associated with the RACH
occasion. In some implementations, the apparatus may include means
for transmitting a synchronization signal block that identifies a
particular time-frequency resource allocation of the respective
time-frequency resource allocations. Such means may include one or
more components described elsewhere herein.
Aspects generally include a method, apparatus, system, computer
program product, non-transitory computer-readable medium, user
equipment, base station, wireless communication device, and
processing system as substantially described herein with reference
to and as illustrated by the accompanying drawings.
Details of one or more implementations of the subject matter
described in this disclosure are set forth in the accompanying
drawings and the description below. Other features, aspects, and
advantages will become apparent from the description, the drawings
and the claims. Note that the relative dimensions of the following
figures may not be drawn to scale.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram conceptually illustrating an example of a
wireless network.
FIG. 2 is a block diagram conceptually illustrating an example of a
base station in communication with a UE in a wireless network.
FIG. 3 is a diagram illustrating an example of a two-step random
access procedure.
FIG. 4 is a diagram illustrating an example of a random access
procedure using random access channel (RACH) occasions that are
associated with a same time-frequency resource allocation.
FIG. 5 is a diagram illustrating an example process performed, for
example, by a user equipment (UE).
FIG. 6 is a diagram illustrating an example process performed, for
example, by a base station (BS).
FIG. 7 is a diagram illustrating an example of frequency division
multiplexed RACH occasions and a set of virtual RACH occasions
associated with a same time-frequency resource or a same RACH
occasion.
FIG. 8 is a diagram illustrating examples of implicit derivation of
preamble sequences.
Like reference numbers and designations in the various drawings
indicate like elements.
DETAILED DESCRIPTION
The following description is directed to certain implementations
for the purposes of describing the innovative aspects of this
disclosure. However, a person having ordinary skill in the art will
readily recognize that the teachings herein can be applied in a
multitude of different ways. Some of the examples in this
disclosure are based on wireless and wired local area network (LAN)
communication according to the Institute of Electrical and
Electronics Engineers (IEEE) 802.11 wireless standards, the IEEE
802.3 Ethernet standards, and the IEEE 1901 Powerline communication
(PLC) standards. However, the described implementations may be
implemented in any device, system or network that is capable of
transmitting and receiving radio frequency signals according to any
of the wireless communication standards, including any of the IEEE
802.11 standards, the Bluetooth.RTM. standard, code division
multiple access (CDMA), frequency division multiple access (FDMA),
time division multiple access (TDMA), Global System for Mobile
communications (GSM), GSM/General Packet Radio Service (GPRS),
Enhanced Data GSM Environment (EDGE), Terrestrial Trunked Radio
(TETRA), Wideband-CDMA (W-CDMA), Evolution Data Optimized (EV-DO),
1.times.EV-DO, EV-DO Rev A, EV-DO Rev B, High Speed Packet Access
(HSPA), High Speed Downlink Packet Access (HSDPA), High Speed
Uplink Packet Access (HSUPA), Evolved High Speed Packet Access
(HSPA+), Long Term Evolution (LTE), AMPS, or other known signals
that are used to communicate within a wireless, cellular or
internet of things (IOT) network, such as a system utilizing 3G, 4G
or 5G, or further implementations thereof, technology.
A user equipment (UE) may access a network provided by a base
station (BS) using a random access channel (RACH) procedure. For
example, the UE may transmit a RACH preamble on a selected RACH
occasion to trigger a RACH procedure. In some cases, multiple RACH
occasions may be frequency division multiplexed, which may improve
spectral efficiency and increase the number of UEs that can
transmit RACH preambles without colliding with each other. For
example, a synchronization signal block (SSB) transmitted by a base
station may map to multiple RACH occasions in the frequency domain,
and a UE that receives the SSB may select one of the RACH occasions
on which to transmit a RACH preamble. However, for some radio
access technologies (RATs), such as NR-unlicensed (NR-U), occupied
channel bandwidth (OCB) requirements may necessitate the occupation
of a threshold percentage of the available bandwidth of a band
(such as, for example, approximately 60 percent, 65 percent, 70
percent, 75 percent, 80 percent, 85 percent, etc.). In such
instances, a longer RACH preamble may be used. For example, the
longer RACH preamble may be longer than a baseline RACH preamble
length, which may satisfy the OCB requirement, improve maximum
coupling loss (MCL) performance, and increase capacity. However,
frequency division multiplexing may be impractical when the longer
RACH preamble is used due to the increased size of the RACH
message.
Some techniques and apparatuses described herein provide RACH
occasions that overlap in frequency. For example, a set of RACH
occasions may be associated with the same time-frequency resources
or a same RACH occasion. A set of RACH occasions associated with
the same time-frequency resources or the same RACH occasion may be
referred to as virtual RACH occasions. Each RACH occasion of the
set of RACH occasions may be associated with a different set of
RACH preambles. An SSB may identify a particular time-frequency
resource, and a UE that receives the SSB may select one of the RACH
occasions associated with the particular time-frequency resource.
The UE may transmit a RACH preamble associated with the selected
RACH occasion.
Particular implementations of the subject matter described in this
disclosure can be implemented to realize one or more of the
following potential advantages. Random access capacity of certain
bands (such as NR-U bands or other bands with OCB requirements) may
be increased, thereby increasing capacity of such bands and
potentially reducing delay associated with initial access.
Furthermore, the OCB requirements of such bands may be satisfied by
the usage of longer RACH sequences without sacrificing random
access capacity as would occur without the usage of virtual RACH
occasions.
FIG. 1 is a block diagram conceptually illustrating an example of a
wireless network 100. The wireless network 100 may be an LTE
network or some other wireless network, such as a 5G or NR network.
Wireless network 100 may include a number of BSs 110 (shown as BS
110a, BS 110b, BS 110c, and BS 110d) and other network entities. A
BS is an entity that communicates with user equipment (UEs) and
also may be referred to as a base station, a NR BS, a Node B, a
gNB, a 5G node B (NB), an access point, a transmit receive point
(TRP), or the like. Each BS may provide communication coverage for
a particular geographic area. In 3GPP, the term "cell" can refer to
a coverage area of a BS, a BS subsystem serving this coverage area,
or a combination thereof, depending on the context in which the
term is used.
A BS may provide communication coverage for a macro cell, a pico
cell, a femto cell, another type of cell, or a combination thereof.
A macro cell may cover a relatively large geographic area (for
example, several kilometers in radius) and may allow unrestricted
access by UEs with service subscription. A pico cell may cover a
relatively small geographic area and may allow unrestricted access
by UEs with service subscription. A femto cell may cover a
relatively small geographic area (for example, a home) and may
allow restricted access by UEs having association with the femto
cell (for example, UEs in a closed subscriber group (CSG)). A BS
for a macro cell may be referred to as a macro BS. ABS for a pico
cell may be referred to as a pico BS. A BS for a femto cell may be
referred to as a femto BS or a home BS. In the example shown in
FIG. 1, a BS 110a may be a macro BS for a macro cell 102a, a BS
110b may be a pico BS for a pico cell 102b, and a BS 110c may be a
femto BS for a femto cell 102c. A BS may support one or multiple
(for example, three) cells. The terms "eNB", "base station", "NR
BS", "gNB", "TRP", "AP", "node B", "5G NB", and "cell" may be used
interchangeably herein.
In some examples, a cell may not necessarily be stationary, and the
geographic area of the cell may move according to the location of a
mobile BS. In some examples, the BSs may be interconnected to one
another as well as to one or more other BSs or network nodes (not
shown) in the wireless network 100 through various types of
backhaul interfaces, such as a direct physical connection, a
virtual network, or a combination thereof using any suitable
transport network.
Wireless network 100 also may include relay stations. A relay
station is an entity that can receive a transmission of data from
an upstream station (for example, a BS or a UE) and send a
transmission of the data to a downstream station (for example, a UE
or a BS). A relay station also may be a UE that can relay
transmissions for other UEs. In the example shown in FIG. 1, a
relay station 110d may communicate with macro BS 110a and a UE 120d
in order to facilitate communication between BS 110a and UE 120d. A
relay station also may be referred to as a relay BS, a relay base
station, a relay, etc.
Wireless network 100 may be a heterogeneous network that includes
BSs of different types, for example, macro BSs, pico BSs, femto
BSs, relay BSs, etc. These different types of BSs may have
different transmit power levels, different coverage areas, and
different impacts on interference in wireless network 100. For
example, macro BSs may have a high transmit power level (for
example, 5 to 40 Watts) where pico BSs, femto BSs, and relay BSs
may have lower transmit power levels (for example, 0.1 to 2
Watts).
A network controller 130 may couple to a set of BSs and may provide
coordination and control for these BSs. Network controller 130 may
communicate with the BSs via a backhaul. The BSs also may
communicate with one another, for example, directly or indirectly
via a wireless or wireline backhaul.
UEs 120 (for example, 120a, 120b, 120c) may be dispersed throughout
wireless network 100, and each UE may be stationary or mobile. A UE
also may be referred to as an access terminal, a terminal, a mobile
station, a subscriber unit, a station, etc. A UE may be a cellular
phone (for example, a smart phone), a personal digital assistant
(PDA), a wireless modem, a wireless communication device, a
handheld device, a laptop computer, a cordless phone, a wireless
local loop (WLL) station, a tablet, a camera, a gaming device, a
netbook, a smartbook, an ultrabook, a medical device or equipment,
biometric sensors/devices, wearable devices (smart watches, smart
clothing, smart glasses, smart wrist bands, smart jewelry (for
example, smart ring, smart bracelet)), an entertainment device (for
example, a music or video device, or a satellite radio), a
vehicular component or sensor, smart meters/sensors, industrial
manufacturing equipment, a global positioning system device, or any
other suitable device that is configured to communicate via a
wireless or wired medium.
Some UEs may be considered machine-type communication (MTC) or
evolved or enhanced machine-type communication (eMTC) UEs. MTC and
eMTC UEs include, for example, robots, drones, remote devices,
sensors, meters, monitors, location tags, etc., that may
communicate with a base station, another device (for example,
remote device), or some other entity. A wireless node may provide,
for example, connectivity for or to a network (for example, a wide
area network such as Internet or a cellular network) via a wired or
wireless communication link. Some UEs may be considered
Internet-of-Things (IoT) devices or may be implemented as NB-IoT
(narrowband internet of things) devices. Some UEs may be considered
a Customer Premises Equipment (CPE). UE 120 may be included inside
a housing that houses components of UE 120, such as processor
components, memory components, similar components, or a combination
thereof.
In general, any number of wireless networks may be deployed in a
given geographic area. Each wireless network may support a
particular RAT and may operate on one or more frequencies. A RAT
also may be referred to as a radio technology, an air interface,
etc. A frequency also may be referred to as a carrier, a frequency
channel, etc. Each frequency may support a single RAT in a given
geographic area in order to avoid interference between wireless
networks of different RATs. In some cases, NR or 5G RAT networks
may be deployed.
In some examples, access to the air interface may be scheduled,
where a scheduling entity (for example, a base station) allocates
resources for communication among some or all devices and equipment
within the scheduling entity's service area or cell. Within the
present disclosure, as discussed further below, the scheduling
entity may be responsible for scheduling, assigning, reconfiguring,
and releasing resources for one or more subordinate entities. That
is, for scheduled communication, subordinate entities utilize
resources allocated by the scheduling entity.
Base stations are not the only entities that may function as a
scheduling entity. That is, in some examples, a UE may function as
a scheduling entity, scheduling resources for one or more
subordinate entities (for example, one or more other UEs). In this
example, the UE is functioning as a scheduling entity, and other
UEs utilize resources scheduled by the UE for wireless
communication. A UE may function as a scheduling entity in a
peer-to-peer (P2P) network, in a mesh network, or another type of
network. In a mesh network example, UEs may optionally communicate
directly with one another in addition to communicating with the
scheduling entity.
Thus, in a wireless communication network with a scheduled access
to time-frequency resources and having a cellular configuration, a
P2P configuration, and a mesh configuration, a scheduling entity
and one or more subordinate entities may communicate utilizing the
scheduled resources.
In some aspects, two or more UEs 120 (for example, shown as UE 120a
and UE 120e) may communicate directly using one or more sidelink
channels (for example, without using a base station 110 as an
intermediary to communicate with one another). For example, the UEs
120 may communicate using peer-to-peer (P2P) communications,
device-to-device (D2D) communications, a vehicle-to-everything
(V2X) protocol (which may include a vehicle-to-vehicle (V2V)
protocol, a vehicle-to-infrastructure (V2I) protocol, or similar
protocol), a mesh network, or similar networks, or combinations
thereof. In this case, the UE 120 may perform scheduling
operations, resource selection operations, as well as other
operations described elsewhere herein as being performed by the
base station 110.
FIG. 2 is a block diagram conceptually illustrating an example 200
of a base station 110 in communication with a UE 120. In some
aspects, base station 110 and UE 120 may respectively be one of the
base stations and one of the UEs in wireless network 100 of FIG. 1.
Base station 110 may be equipped with T antennas 234a through 234t,
and UE 120 may be equipped with R antennas 252a through 252r, where
in general T.gtoreq.1 and R.gtoreq.1.
At base station 110, a transmit processor 220 may receive data from
a data source 212 for one or more UEs, select one or more
modulation and coding schemes (MCS) for each UE based at least in
part on channel quality indicators (CQIs) received from the UE,
process (for example, encode and modulate) the data for each UE
based at least in part on the MCS(s) selected for the UE, and
provide data symbols for all UEs. The transmit processor 220 also
may process system information (for example, for semi-static
resource partitioning information (SRPI), etc.) and control
information (for example, CQI requests, grants, upper layer
signaling, etc.) and provide overhead symbols and control symbols.
The transmit processor 220 also may generate reference symbols for
reference signals (for example, the cell-specific reference signal
(CRS)) and synchronization signals (for example, the primary
synchronization signal (PSS) and secondary synchronization signal
(SSS)). A transmit (TX) multiple-input multiple-output (MIMO)
processor 230 may perform spatial processing (for example,
precoding) on the data symbols, the control symbols, the overhead
symbols, or the reference symbols, if applicable, and may provide T
output symbol streams to T modulators (MODs) 232a through 232t.
Each modulator 232 may process a respective output symbol stream
(for example, for OFDM, etc.) to obtain an output sample stream.
Each modulator 232 may further process (for example, convert to
analog, amplify, filter, and upconvert) the output sample stream to
obtain a downlink signal. T downlink signals from modulators 232a
through 232t may be transmitted via T antennas 234a through 234t,
respectively. According to various aspects described in more detail
below, the synchronization signals can be generated with location
encoding to convey additional information.
At UE 120, antennas 252a through 252r may receive the downlink
signals from base station 110 or other base stations and may
provide received signals to demodulators (DEMODs) 254a through
254r, respectively. Each demodulator 254 may condition (for
example, filter, amplify, downconvert, and digitize) a received
signal to obtain input samples. Each demodulator 254 may further
process the input samples (for example, for OFDM, etc.) to obtain
received symbols. A MIMO detector 256 may obtain received symbols
from all R demodulators 254a through 254r, perform MIMO detection
on the received symbols if applicable, and provide detected
symbols. A receive processor 258 may process (for example,
demodulate and decode) the detected symbols, provide decoded data
for UE 120 to a data sink 260, and provide decoded control
information and system information to a controller or processor
(controller/processor) 280. A channel processor may determine
reference signal received power (RSRP), received signal strength
indicator (RSSI), reference signal received quality (RSRQ), channel
quality indicator (CQI), etc. In some aspects, one or more
components of UE 120 may be included in a housing.
On the uplink, at UE 120, a transmit processor 264 may receive and
process data from a data source 262 and control information (for
example, for reports including RSRP, RSSI, RSRQ, CQI, etc.) from
controller/processor 280. Transmit processor 264 also may generate
reference symbols for one or more reference signals. The symbols
from transmit processor 264 may be precoded by a TX MIMO processor
266 if applicable, further processed by modulators 254a through
254r (for example, for DFT-s-OFDM, CP-OFDM, etc.), and transmitted
to base station 110. At base station 110, the uplink signals from
UE 120 and other UEs may be received by antennas 234, processed by
demodulators 232, detected by a MIMO detector 236 if applicable,
and further processed by a receive processor 238 to obtain decoded
data and control information sent by UE 120. Receive processor 238
may provide the decoded data to a data sink 239 and the decoded
control information to a controller or processor (i.e.,
controller/processor) 240. The base station 110 may include
communication unit 244 and communicate to network controller 130
via communication unit 244. The network controller 130 may include
communication unit 294, a controller or processor (i.e.,
controller/processor) 290, and memory 292.
In some implementations, controller/processor 280 may be a
component of a processing system. A processing system may generally
refer to a system or series of machines or components that receives
inputs and processes the inputs to produce a set of outputs (which
may be passed to other systems or components of, for example, the
UE 120). For example, a processing system of the UE 120 may refer
to a system including the various other components or subcomponents
of the UE 120.
The processing system of the UE 120 may interface with other
components of the UE 120, and may process information received from
other components (such as inputs or signals), output information to
other components, etc. For example, a chip or modem of the UE 120
may include a processing system, a first interface configured to
receive or obtain information, and a second interface configured to
output, transmit or provide information. In some cases, the first
interface may refer to an interface between the processing system
of the chip or modem and a receiver, such that the UE 120 may
receive information or signal inputs, and the information may be
passed to the processing system. In some cases, the second
interface may refer to an interface between the processing system
of the chip or modem and a transmitter, such that the UE 120 may
transmit information output from the chip or modem. A person having
ordinary skill in the art will readily recognize that the second
interface also may obtain or receive information or signal inputs,
and the first interface also may output, transmit or provide
information.
In some implementations, controller/processor 240 may be a
component of a processing system. A processing system may generally
refer to a system or series of machines or components that receives
inputs and processes the inputs to produce a set of outputs (which
may be passed to other systems or components of, for example, the
BS 110). For example, a processing system of the BS 110 may refer
to a system including the various other components or subcomponents
of the BS 110.
The processing system of the BS 110 may interface with other
components of the BS 110, and may process information received from
other components (such as inputs or signals), output information to
other components, etc. For example, a chip or modem of the BS 110
may include a processing system, a first interface configured to
receive or obtain information, and a second interface configured to
output, transmit or provide information. In some cases, the first
interface may refer to an interface between the processing system
of the chip or modem and a receiver, such that the BS 110 may
receive information or signal inputs, and the information may be
passed to the processing system. In some cases, the second
interface may refer to an interface between the processing system
of the chip or modem and a transmitter, such that the BS 110 may
transmit information output from the chip or modem. A person having
ordinary skill in the art will readily recognize that the second
interface also may obtain or receive information or signal inputs,
and the first interface also may output, transmit or provide
information.
The controller/processor 240 of base station 110, the
controller/processor 280 of UE 120, or any other component(s) of
FIG. 2 may perform one or more techniques associated with a random
access procedure using random access channel occasions that are
associated with a same time-frequency resource allocation, as
described in more detail elsewhere herein. For example, the
controller/processor 240 of base station 110, the
controller/processor 280 of UE 120, or any other component(s) (or
combinations of components) of FIG. 2 may perform or direct
operations of, for example, the process 500 of FIG. 5, or other
processes as described herein. The memories 242 and 282 may store
data and program codes for base station 110 and UE 120,
respectively. A scheduler 246 may schedule UEs for data
transmission on the downlink, the uplink, or a combination
thereof.
The stored program codes, when executed by the controller/processor
280 or other processors and modules at UE 120, may cause the UE 120
to perform operations described with respect to the process 400 of
FIG. 4, or other processes as described herein. The stored program
codes, when executed by the controller/processor 240 or other
processors and modules at base station 110, may cause the base
station 110 to perform operations described with respect to the
process 600 of FIG. 6, or other processes as described herein. A
scheduler 246 may schedule UEs for data transmission on the
downlink, the uplink, or a combination thereof.
The UE 120 may include means for performing one or more operations
described herein, such as the process 400 of FIG. 4 or other
processes as described herein. In some aspects, such means may
include one or more components of UE 120 described in connection
with FIG. 2. The base station 110 may include means for performing
one or more operations described herein, such as the process 500 of
FIG. 5 or other processes as described herein. In some aspects,
such means may include one or more components of base station 110
described in connection with FIG. 2.
While blocks in FIG. 2 are illustrated as distinct components, the
functions described above with respect to the blocks may be
implemented in a single hardware, software, or combination
component or in various combinations of components. For example,
the functions described with respect to the transmit processor 264,
the receive processor 258, the TX MIMO processor 266, or another
processor may be performed by or under the control of the
controller/processor 280.
FIG. 3 is a diagram illustrating an example 300 of a two-step
random access procedure, in accordance with various aspects of the
present disclosure. As shown in FIG. 3, a base station 110 and a UE
120 may communicate with one another to perform the two-step random
access procedure.
As shown by reference number 305, the base station 110 may
transmit, and the UE 120 may receive, one or more synchronization
signal blocks (SSBs) and random access configuration information.
In some aspects, the random access configuration information may be
transmitted in or indicated by system information (such as in one
or more system information blocks (SIBs)) or an SSB, such as for
contention-based random access. Additionally, or alternatively, the
random access configuration information may be transmitted in a
radio resource control (RRC) message or a physical downlink control
channel (PDCCH) order message that triggers a RACH procedure, such
as for contention-free random access. The random access
configuration information may include one or more parameters to be
used in the two-step random access procedure, such as one or more
parameters for transmitting a random access message (illustrated as
"RAM"), receiving a random access response (RAR) to the random
access message, or the like. In some aspects, the SSB may identify
a time-frequency resource associated with a plurality of RACH
occasions.
As shown by reference number 310, the UE 120 may transmit, and the
base station 110 may receive, a random access message preamble. As
shown by reference number 315, the UE 120 may transmit, and the
base station 110 may receive, a random access message payload. As
shown, the UE 120 may transmit the random access message preamble
and the random access message payload to the base station 110 as
part of an initial (or first) step of the two-step random access
procedure. In some aspects, the random access message may be
referred to as message A, msgA, a first message, or an initial
message, in a two-step random access procedure. Furthermore, in
some aspects, the random access message preamble may be referred to
as a message A preamble, a msgA preamble, a preamble, or a physical
random access channel (PRACH) preamble, and the random access
message payload may be referred to as a message A payload, a msgA
payload, or a payload. In some aspects, the random access message
may include some or all of the contents of message 1 (msg1) and
message 3 (msg3) of a four-step random access procedure. For
example, the random access message preamble may include some or all
contents of message 1 (such as a PRACH preamble), and the random
access message payload may include some or all contents of message
3 (such as a UE identifier, uplink control information (UCI), a
physical uplink shared channel (PUSCH) transmission, or other
information). The random access message preamble and payload may be
transmitted on a selected RACH occasion, of a set of at least
partially overlapping RACH occasions associated with the
time-frequency resource identified by the SSB.
As shown by reference number 320, the base station 110 may receive
the random access message preamble transmitted by the UE 120. If
the base station 110 successfully receives and decodes the random
access message preamble, the base station 110 may then receive and
decode the random access message payload.
As shown by reference number 325, the base station 110 may transmit
an RAR (sometimes referred to as an RAR message). As shown, the
base station 110 may transmit the RAR message as part of a second
step of the two-step random access procedure. In some aspects, the
RAR message may be referred to as message B, msgB, or a second
message in a two-step random access procedure. The RAR message may
include some or all of the contents of message 2 (msg2) and message
4 (msg4) of a four-step random access procedure. For example, the
RAR message may include the detected PRACH preamble identifier, the
detected UE identifier, a timing advance value, or contention
resolution information.
As shown by reference number 330, as part of the second step of the
two-step random access procedure, the base station 110 may transmit
a physical downlink control channel (PDCCH) communication for the
RAR. The PDCCH communication may schedule a physical downlink
shared channel (PDSCH) communication that includes the RAR. For
example, the PDCCH communication may indicate a resource allocation
(such as in downlink control information (DCI)) for the PDSCH
communication.
As shown by reference number 335, as part of the second step of the
two-step random access procedure, the base station 110 may transmit
the PDSCH communication for the RAR, as scheduled by the PDCCH
communication. The RAR may be included in a medium access control
(MAC) protocol data unit (PDU) of the PDSCH communication. As shown
by reference number 340, if the UE 120 successfully receives the
RAR, the UE 120 may transmit a hybrid automatic repeat request
(HARD) acknowledgement (ACK).
FIG. 4 is a diagram illustrating an example 400 of a random access
procedure using random access channel (RACH) occasions that are
associated with a same time-frequency resource allocation. As
shown, the example 400 includes a UE 120 and a BS 110. The BS 110
may provide access to a network. For example, the BS 110 may
provide access to a network on a band or sub-band associated with
an occupied channel bandwidth (OCB) threshold, such as an NR-U band
or sub-band, or the like. In some aspects, the band or sub-band may
be a wideband, such as a 20 MHz sub-band.
The BS 110 may provide configuration information 410 to the UE 120.
As further shown, the configuration information 410 may identify a
time-frequency (TF) resource allocation 420 (i.e., TF Alloc. 1) for
a set of RACH occasions (RACH Occasions 1, 2, and 3, shown by
reference number 430). In some aspects, the configuration
information 410 may be provided as radio resource control (RRC)
information, downlink control information (DCI), a system
information block (SIB), a master information block (MIB), or the
like.
As shown, the configuration information 410 may identify a TF
resource allocation 420 associated with a set of RACH occasions
430. For example, each RACH occasion of the set of RACH occasions
430 may use the TF resource allocation 420. Thus, the set of RACH
occasions 430 may overlap in time and in frequency. Each RACH
occasion, of the set of RACH occasions 430, may be associated with
a different set of sequences. For example, a RACH preamble may be
generated in accordance with a sequence, and a BS 110 may respond
to the RACH preamble based on the sequence and using resources
corresponding to a RACH occasion associated with the sequence. By
assigning each RACH occasion a different set of sequences, such as
preamble sequence sets, the RACH occasions may be differentiated
from each other even though the RACH occasions overlap each other
in time and in frequency. Thus, a longer RACH preamble, that
satisfies the OCB threshold of the band on which the RACH preamble
is transmitted, may be used without sacrificing random access
capacity.
In some aspects, the TF resource allocation 420 may be for a legacy
RACH occasion. In such a case, a set of virtual RACH occasions may
be mapped to the TF resource allocation 420 of the legacy RACH
allocation. In other words, a set of virtual RACH occasions (such
as the set of RACH occasions 430) may be associated with a legacy
RACH occasion and may overlap each other within the legacy RACH
occasion's TF resource allocation 420. Legacy RACH occasions may be
associated with a same set of sequences and different time
resources or different frequency resources, and virtual RACH
occasions associated with a particular legacy RACH occasion may be
differentiated by the different sets of sequences assigned to the
virtual RACH occasions. In this case, the configuration information
410 may identify the TF resource allocation 420 directly (in terms
of time and frequency resources) or as a function of the legacy
RACH occasion (by identifying the legacy RACH occasion and the
sequences of each virtual RACH occasion that is to use the TF
resource allocation 420 of the legacy RACH occasion).
The TF resource allocation 420 may be associated with any integer
number of RACH occasions, such as one RACH occasion, two RACH
occasions, three RACH occasions, four RACH occasions, eight RACH
occasions, and so on. In some aspects, the configuration
information 410 may indicate how many RACH occasions are associated
with a TF resource allocation 420, such as with an indicator of a
number of RACH occasions included in the set of RACH occasions 430,
or by providing configuration information for each RACH occasion of
the set of RACH occasions 430.
The BS 110 (and alternatively the UE 120) may determine a preamble
sequence that is included in a RACH occasion. For example, there
may be X RACH occasions per TF resource allocation 420 (or in other
words, X virtual RACH occasions per legacy RACH occasion). In this
case, and assuming 64 sequences per RACH occasion, there may be
64.times.X sequences for the TF resource allocation 420. Each RACH
occasion may be associated with a set of roots. The set of roots
may be identified by a table that indicates the set of roots and an
order in which roots of the set of roots are to be used. In some
aspects, the table may indicate that the roots are to be used in an
ascending order ([1 2 3 4 5 . . . ]). In some aspects, the table
may indicate that the roots are to be used in a descending order
(for example, when the RACH occasion includes 607 symbols, then the
table may include [606 605 604 603 . . . ]). In some aspects, the
table may indicate that the roots are to alternate between
ascending values and descending values (for example, when the RACH
occasion includes 607 symbols, then the table may include [1 606 2
605 3 604 4 603 . . . ]). Other forms may be used for the table,
and the implementations described herein are not limited to any
particular arrangement of the table. The BS 110 may start at a
first root of the set of roots and may select up to 64 preamble
sequences using a configured cyclic shift step size until all
allowed cyclic shift values are used. If the cyclic shift values
are exhausted for the first root, the BS 110 may move to a next
root, and may select preamble sequences until all the cyclic shift
values are used for this root. This may continue until 64 preamble
sequences have been selected for the RACH occasion.
In some aspects, the starting root may be implicitly derived for a
RACH occasion. As a first option, if a first RACH occasion is
completed partway through a particular root, then a second RACH
occasion may begin with the next sequence using the current root
where the first RACH occasion was completed. As a second option, if
a first RACH occasion is completed partway through a particular
root, then a second RACH occasion may begin at the beginning of a
next root. In some aspects, the starting root may be explicitly
configured for each RACH occasion, which may provide increased
flexibility of configuration of starting roots. For an example of
implicit derivation using the first option and the second option,
refer to FIG. 8.
As shown by reference number 440, the BS 110 may transmit a
synchronization signal block (SSB) to the UE 120. The SSB may
include information related to the TF resource allocation 420. For
example, the SSB may identify time and frequency resources of the
TF resource allocation 420, or may identify a legacy RACH occasion
associated with the TF resource allocation 420.
As shown by reference number 450, the UE 120 may select a RACH
occasion of the set of RACH occasions 430 associated with the TF
resource allocation 420. In some aspects, the UE 120 may select the
RACH occasion randomly. In some aspects, the UE 120 may select the
RACH occasion pseudo-randomly. In some aspects, the UE 120 may
select the RACH occasion based on a value associated with the
UE.
As shown by reference number 460, the UE 120 may transmit a RACH
preamble, of the selected RACH occasion, on the TF resource
allocation 420. For example, the UE 120 may generate a RACH
preamble of the selected RACH occasion in accordance with the
configuration information and using one or more of the procedures
for determining a preamble sequence described above. The techniques
described herein can be applied for a two-step RACH procedure
(where the UE 120's RACH message includes a preamble and a payload,
as shown in FIG. 3) or for a four-step RACH procedure (where the UE
120's RACH message includes only a preamble). Thus, the UE 120 may
perform random access using a preamble associated with a selected
RACH occasion, of multiple RACH occasions associated with a
particular TF resource allocation.
FIG. 5 is a diagram illustrating an example process 500 performed,
for example, by a user equipment. The process 500 shows where a UE
(such as user equipment 120 or the like) performs operations
associated with a random access procedure using random access
channel occasions that are associated with a same time-frequency
resource allocation.
As shown in FIG. 5, in some aspects, the process 500 may include
receiving configuration information associated with two or more
RACH occasions, where the configuration information indicates
preamble sequence sets for the two or more RACH occasions, and
where each of the two or more RACH occasions is associated with a
respective preamble sequence set (block 510). For example, the UE
(using antenna 252, DEMOD 254, MIMO detector 256, receive processor
258, controller/processor 280, or the like) may receive
configuration information associated with two or more RACH
occasions, as described above. In some aspects, the configuration
information indicates preamble sequence sets for the two or more
RACH occasions. In some aspects, each of the two or more RACH
occasions is associated with a respective preamble sequence set. In
some aspects, a first interface of the UE may receive configuration
information associated with two or more RACH occasions.
As shown in FIG. 5, in some aspects, the process 500 may include
selecting a RACH occasion, of the two or more RACH occasions (block
520). For example, the UE (using controller/processor 280, transmit
processor 264, TX MIMO processor 266, MOD 254, antenna 252, or the
like) may select a RACH occasion, of the two or more RACH
occasions, as described above. In some aspects, a processing system
of the UE may select a RACH occasion, of the two or more RACH
occasions.
As shown in FIG. 5, in some aspects, the process 500 may include
transmitting a RACH preamble on the selected RACH occasion in
accordance with the preamble sequence associated with the RACH
occasion (block 530). For example, the UE (using
controller/processor 280, transmit processor 264, TX MIMO processor
266, MOD 254, antenna 252, a second interface or the like) may
transmit or output, for transmission, a RACH preamble on the
selected RACH occasion in accordance with a preamble sequence, of
the preamble sequence sets, associated with the selected RACH
occasion, as described above. In some aspects, a second interface
of the UE may output a RACH preamble for transmission on the
selected RACH occasion in accordance with a preamble sequence, of
the preamble sequence sets, associated with the selected RACH
occasion.
The process 500 may include additional aspects, such as any single
aspect or any combination of aspects described below or in
connection with one or more other processes described elsewhere
herein.
In a first aspect, the RACH preamble occupies a threshold channel
bandwidth of a channel in accordance with an occupied channel
bandwidth requirement of the UE.
In a second aspect, alone or in combination with the first aspect,
each RACH occasion of the two or more RACH occasions is associated
with a same time-frequency resource allocation.
In a third aspect, alone or in combination with one or more of the
first and second aspects, the two or more RACH occasions are
associated with respective time-frequency resource allocations.
In a fourth aspect, alone or in combination with one or more of the
first through third aspects, the UE (such as a fourth interface of
the UE) may receive an SSB that identifies a particular
time-frequency resource allocation of the respective time-frequency
resource allocations, where transmitting the RACH preamble on the
selected RACH occasion is based on the selected RACH occasion being
associated with the particular time-frequency resource
allocation.
In a fifth aspect, alone or in combination with one or more of the
first through fourth aspects, the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more RACH occasions, where preamble sequence sets for
one or more other RACH occasions, of the two or more RACH
occasions, are derived based on the first preamble sequence
set.
In a sixth aspect, alone or in combination with one or more of the
first through fifth aspects, the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more RACH occasions, where a second preamble sequence
set for a second RACH occasion of the two or more RACH occasions
starts at a last-used root and a next sequence after a last-used
sequence of the first preamble sequence set.
In a seventh aspect, alone or in combination with one or more of
the first through sixth aspects, the configuration information
identifies a first preamble sequence set for a first RACH occasion,
of the two or more RACH occasions, where a second preamble sequence
set for a second RACH occasion of the two or more RACH occasions
starts at a next root after a last-used root of the first preamble
sequence set.
In an eighth aspect, alone or in combination with one or more of
the first through seventh aspects, the configuration information
identifies respective root sequences for the respective preamble
sequence sets.
In a ninth aspect, alone or in combination with one or more of the
first through eighth aspects, the configuration information
indicates a number of RACH occasions associated with a particular
time-frequency resource allocation.
Although FIG. 5 shows example blocks of the process 500, in some
aspects, the process 500 may include additional blocks, fewer
blocks, different blocks, or differently arranged blocks than those
depicted in FIG. 5. Additionally, or alternatively, two or more of
the blocks of the process 500 may be performed in parallel.
FIG. 6 is a diagram illustrating an example process 600 performed,
for example, by a base station. The process 600 shows where a base
station (such as base station 110 or the like) performs operations
associated with a random access procedure using random access
channel occasions that are associated with a same time-frequency
resource allocation.
As shown in FIG. 6, in some aspects, the process 600 may include
transmitting configuration information associated with two or more
RACH occasions, where the configuration information indicates
preamble sequence sets for the two or more RACH occasions, and
where each of the two or more RACH occasions is associated with a
respective preamble sequence set (block 610). For example, the base
station (using controller/processor 240, transmit processor 220, TX
MIMO processor 230, MOD 232, antenna 234, or the like) may transmit
configuration information associated with two or more RACH
occasions, as described above. In some aspects, the configuration
information indicates preamble sequence sets for the two or more
RACH occasions. In some aspects, each of the two or more RACH
occasions is associated with a respective preamble sequence set. In
some aspects, a first interface of the base station may transmit
configuration information associated with two or more RACH
occasions.
As shown in FIG. 6, in some aspects, the process 600 may include
receiving a RACH preamble on a selected RACH occasion, of the two
or more RACH occasions, in accordance with the preamble sequence
associated with the RACH occasion (block 620). For example, the
base station (using antenna 234, DEMOD 232, MIMO detector 236,
receive processor 238, controller/processor 240, or the like) may
receive a RACH preamble on a selected RACH occasion, of the two or
more RACH occasions, in accordance with a preamble sequence, of the
preamble sequence sets, associated with the selected RACH occasion,
as described above. In some aspects, a second interface of the base
station may receive a RACH preamble on a selected RACH occasion, of
the two or more RACH occasions, in accordance with a preamble
sequence, of the respective preamble sequence sets, associated with
the selected RACH occasion.
The process 600 may include additional aspects, such as any single
aspect or any combination of aspects described below or in
connection with one or more other processes described elsewhere
herein.
In a first aspect, the RACH preamble occupies a threshold channel
bandwidth of a channel in accordance with an occupied channel
bandwidth requirement of the UE.
In a second aspect, alone or in combination with the first aspect,
the two or more RACH occasions are associated with respective
time-frequency resource allocations.
In a third aspect, alone or in combination with one or more of the
first and second aspects, the base station (such as the first
interface of the base station) may transmit or output for
transmission a synchronization signal block that identifies a
particular time-frequency resource allocation of the respective
time-frequency resource allocations, where receiving the RACH
preamble on the selected RACH occasion is based on the selected
RACH occasion being associated with the particular time-frequency
resource allocation.
In a fourth aspect, alone or in combination with one or more of the
first through third aspects, the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more RACH occasions, where preamble sequence sets for
one or more other RACH occasions, of the two or more RACH
occasions, are derived based on the first preamble sequence
set.
In a fifth aspect, alone or in combination with one or more of the
first through fourth aspects, the configuration information
identifies a first preamble sequence set for a first RACH occasion
of the two or more RACH occasions, where a second preamble sequence
set for a second RACH occasion of the two or more RACH occasions
starts at a last-used root and a next sequence after a last-used
sequence of the first preamble sequence set.
In a sixth aspect, alone or in combination with one or more of the
first through fifth aspects, the configuration information
identifies a first preamble sequence set for a first RACH occasion,
of the two or more RACH occasions, where a second preamble sequence
set for a second RACH occasion of the two or more RACH occasions
starts at a next root after a last-used root of the first preamble
sequence set.
In a seventh aspect, alone or in combination with one or more of
the first through sixth aspects, the configuration information
identifies respective root sequences for the respective preamble
sequence sets.
In an eighth aspect, alone or in combination with one or more of
the first through seventh aspects, the configuration information
indicates a number of RACH occasions associated with a particular
time-frequency resource allocation.
Although FIG. 6 shows example blocks of the process 600, in some
aspects, the process 600 may include additional blocks, fewer
blocks, different blocks, or differently arranged blocks than those
depicted in FIG. 6. Additionally, or alternatively, two or more of
the blocks of the process 600 may be performed in parallel.
FIG. 7 is a diagram illustrating an example of frequency division
multiplexed RACH occasions (shown by reference number 710) and a
set of virtual RACH occasions associated with a same time-frequency
resource or a same RACH occasion (shown by reference number 720).
In the frequency division multiplexed case, four RACH occasions
(RO0 through RO3) are multiplexed on a 20 MHz subband. The set of
RACH occasions shown by reference number 720 may each be associated
with the same time-frequency resource, shown by reference number
730, and may each occupy approximately 20 MHz. Thus, each RACH
occasion may satisfy OCB requirements of an unlicensed band while
increasing the random access capacity of such an unlicensed band.
The time-frequency resource is described in more detail in
connection with the TF resource allocation 420 of FIG. 4, and the
four virtual RACH occasions are described in more detail in
connection with the set of RACH occasions 430 of FIG. 4.
As further shown, the set of virtual RACH occasions may be
associated with respective preamble sequence sets, such as
respective sets of 64 preamble sequences. For example, a first
virtual RACH occasion (VRO 0) is associated with a first 64
preamble sequences, a second virtual RACH occasion (VRO 1) is
associated with a second 64 preamble sequences, a third virtual
RACH occasion (VRO 2) is associated with a third 64 preamble
sequences, and a fourth virtual RACH occasion (VRO 3) is associated
with a fourth 64 preamble sequences. These preamble sequence sets
may be computed using implicit root sequences, as described in
connection with FIG. 4.
A UE may receive random access configuration information that
indicates one or more parameters, such as the time-frequency
resource shown by reference number 730, the set of virtual RACH
occasions shown by reference number 720, and the corresponding
preamble sequence sets of each virtual RACH occasion. The UE may
transmit a random access message preamble on a virtual RACH
occasion, and may use a preamble sequence corresponding to the
virtual RACH occasion to generate the random access message
preamble. For example, if the UE selects VRO 2, then the UE may use
a preamble sequence of the third 64 preamble sequences associated
with VRO 2. The UE also may transmit a random access message
payload in association with the random access message preamble.
FIG. 8 is a diagram illustrating examples of implicit derivation of
preamble sequences. Reference number 805 shows implicit derivation
of preamble sequences using a first option in which all sequences
of a given root are used before moving to a next root, and
reference number 810 shows implicit derivation of preamble
sequences using a second option in which each RACH occasion starts
with a different root. In FIG. 8, a RACH occasion is associated
with a length of 607 symbols, a cyclic shift step size of 46, 64
preamble sequences, and a root table indicating roots [1 606 2 605
3 604 . . . ]. In this case, each root can create 13 sequences
(determined as the floor of 607/46).
As shown by reference number 815, in the first option, the BS 110
may generate 52 sequences using roots [1 606 2 605] (13 sequences
from each root). As shown by reference number 820, the BS 110 may
generate 12 sequences using root 3 to finish the preamble sequences
of a first RACH occasion. As shown by reference number 825, the BS
110 may start with the 13.sup.th sequence from root 3 to determine
sequences for a second RACH occasion. As shown by reference number
830, the BS 110 may proceed to use all sequences of roots [604 4
603 5] and a first 11 sequences of root 602 to generate the total
of 64 preamble sequences for the second RACH occasion.
In the second option shown by reference number 810, the generation
of sequences for the first RO is similar to what is described with
regard to the first option. However, as shown by reference number
835, to generate sequences for the second RO, the BS 110 may start
with a first sequence of root 604, may use all sequences of roots
[604 4 603 5], and may use a first 12 sequences of root 602.
The foregoing disclosure provides illustration and description, but
is not intended to be exhaustive or to limit the aspects to the
precise form disclosed. Modifications and variations may be made in
light of the above disclosure or may be acquired from practice of
the aspects.
As used herein, the term "component" is intended to be broadly
construed as hardware, firmware, or a combination of hardware and
software. As used herein, a processor is implemented in hardware,
firmware, or a combination of hardware and software. As used
herein, the phrase "based on" is intended to be broadly construed
to mean "based at least in part on."
Some aspects are described herein in connection with thresholds. As
used herein, satisfying a threshold may refer to a value being
greater than the threshold, greater than or equal to the threshold,
less than the threshold, less than or equal to the threshold, equal
to the threshold, not equal to the threshold, or the like.
As used herein, a phrase referring to "at least one of" a list of
items refers to any combination of those items, including single
members. As an example, "at least one of: a, b, or c" is intended
to cover: a, b, c, a-b, a-c, b-c, and a-b-c.
The various illustrative logics, logical blocks, modules, circuits
and algorithm processes described in connection with the aspects
disclosed herein may be implemented as electronic hardware,
computer software, or combinations of both. The interchangeability
of hardware and software has been described generally, in terms of
functionality, and illustrated in the various illustrative
components, blocks, modules, circuits and processes described
above. Whether such functionality is implemented in hardware or
software depends upon the particular application and design
constraints imposed on the overall system.
The hardware and data processing apparatus used to implement the
various illustrative logics, logical blocks, modules and circuits
described in connection with the aspects disclosed herein may be
implemented or performed with a general purpose single- or
multi-chip processor, a digital signal processor (DSP), an
application specific integrated circuit (ASIC), a field
programmable gate array (FPGA) or other programmable logic device,
discrete gate or transistor logic, discrete hardware components, or
any combination thereof designed to perform the functions described
herein. A general purpose processor may be a microprocessor, or,
any conventional processor, controller, microcontroller, or state
machine. A processor also may be implemented as a combination of
computing devices, for example, a combination of a DSP and a
microprocessor, a plurality of microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration. In some aspects, particular processes and methods
may be performed by circuitry that is specific to a given
function.
In one or more aspects, the functions described may be implemented
in hardware, digital electronic circuitry, computer software,
firmware, including the structures disclosed in this specification
and their structural equivalents thereof, or in any combination
thereof. Aspects of the subject matter described in this
specification also can be implemented as one or more computer
programs, i.e., one or more modules of computer program
instructions, encoded on a computer storage media for execution by,
or to control the operation of, data processing apparatus.
If implemented in software, the functions may be stored on or
transmitted over as one or more instructions or code on a
computer-readable medium. The processes of a method or algorithm
disclosed herein may be implemented in a processor-executable
software module which may reside on a computer-readable medium.
Computer-readable media includes both computer storage media and
communication media including any medium that can be enabled to
transfer a computer program from one place to another. A storage
media may be any available media that may be accessed by a
computer. By way of example, and not limitation, such
computer-readable media may include RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that may be used to store
desired program code in the form of instructions or data structures
and that may be accessed by a computer. Also, any connection can be
properly termed a computer-readable medium. Disk and disc, as used
herein, includes compact disc (CD), laser disc, optical disc,
digital versatile disc (DVD), floppy disk, and Blu-ray disc where
disks usually reproduce data magnetically, while discs reproduce
data optically with lasers. Combinations of the above should also
be included within the scope of computer-readable media.
Additionally, the operations of a method or algorithm may reside as
one or any combination or set of codes and instructions on a
machine readable medium and computer-readable medium, which may be
incorporated into a computer program product.
Various modifications to the aspects described in this disclosure
may be readily apparent to those skilled in the art, and the
generic principles defined herein may be applied to other aspects
without departing from the spirit or scope of this disclosure.
Thus, the claims are not intended to be limited to the aspects
shown herein, but are to be accorded the widest scope consistent
with this disclosure, the principles and the novel features
disclosed herein.
Additionally, a person having ordinary skill in the art will
readily appreciate, the terms "upper" and "lower" are sometimes
used for ease of describing the figures, and indicate relative
positions corresponding to the orientation of the figure on a
properly oriented page, and may not reflect the proper orientation
of any device as implemented.
Certain features that are described in this specification in the
context of separate aspects also can be implemented in combination
in a single aspect. Conversely, various features that are described
in the context of a single aspect also can be implemented in
multiple aspects separately or in any suitable subcombination.
Moreover, although features may be described above as acting in
certain combinations and even initially claimed as such, one or
more features from a claimed combination can in some cases be
excised from the combination, and the claimed combination may be
directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a
particular order, this should not be understood as requiring that
such operations be performed in the particular order shown or in
sequential order, or that all illustrated operations be performed,
to achieve desirable results. Further, the drawings may
schematically depict one more example processes in the form of a
flow diagram. However, other operations that are not depicted can
be incorporated in the example processes that are schematically
illustrated. For example, one or more additional operations can be
performed before, after, simultaneously, or between any of the
illustrated operations. In certain circumstances, multitasking and
parallel processing may be advantageous. Moreover, the separation
of various system components in the aspects described above should
not be understood as requiring such separation in all aspects, and
it should be understood that the described program components and
systems can generally be integrated together in a single software
product or packaged into multiple software products. Additionally,
other aspects are within the scope of the following claims. In some
cases, the actions recited in the claims can be performed in a
different order and still achieve desirable results.
* * * * *
References